The sea ice off West Antarctica, seen here in October 2018, is a dynamic environment that experiences huge annual swings in light level, temperature and salinity, as well as the longer-term shifts of climate change. Algae and other microbes living in and around the sea ice are part of an understudied ecosystem.

Co-authors Hannah Dawson (left) and Susan Rundell collect samples of seawater and sea ice off West Antarctica in November 2018. They put seawater in carboys wrapped in garbage bags (lower right) to avoid light contamination, and use an insulated cooler to store samples of sea ice.

This experimental setup at Palmer Station in West Antarctica in November 2018 let researchers incubate samples at different temperatures and salinities to mimic seasonal changes in Antarctic waters. Results show that seawater microbes can survive these short-term changes by adjusting their production of organic molecules, rather than being replaced by different microbes specifically adapted to those new conditions.